Spring



Julyv 6, 1937. H. KDO y f l 2,086,321 l SPRING Filed April 27.1936

Patented July 6, 1937 UNITED STATES PATENT 2.086.321 y 'I I SPRING V Hiojiro Kuda, Nada-kn, Kobe, Japan, assignor to The Kobe Seikosha Company, Limited, Kobe city, Japan Application April 27, 1936, Serial No.76,654

z claims. (ci. zer-o1) My invention relates to a spring, especially for vehicles. The principal object o1' this spring is to increase its load carrying capacity.

For this object, a frusto-conical and a cylindrical spiral springsection of equal pitches are fitted, inner and outer, by screwing one within the other, in contact with each other at one end, and separating from each other progressively greater distances towards the other end.v The number of spring sections which are to be assem bled and the shape of the material of which the sections are made, may be changed according to the particular duty ythe spring is to perform.`

I have illustrated an embodiment of my invention in the accompanying drawing, in which Figure 1 is a plan view of my composite spring consisting of a frusto-conical and a cylindrical spiral section made of steel wire rods square in cross section.

Fig. 2 is a sectional view along the line 2-2 of Fig. 1.

Fig. 3 is the same sectional view as Fig. 2 showing a compressed state due to an imposed load.

Fig. 4 is a part of Fig. 3 on larger scale, showing the component actions of forces on the inclined surfaces of the sections. V

Fig. 5 is a sectional view of a modification of my invention consisting of two frusto-conical spiral spring sections made of steel wires rods equal in cross section.

Figs. 6 and 'Z are sectional viewsV of modifications showing diierent cross sectional shapes of wire.

Fig. 8 is a chart of curves showing relations between load and deilection of my invention.

Referring to Figs. 1, 2 and 3, the reference characters II and I2 indicate respectivelyv a frusto-conical and a cylindrical spiral spring oi equal pitches composed of steel wire rectangular in cross section wound in the general direction of the diagonal of their cross sections. The conical section is so fitted to the inside of the cylindrical section by screwing into place that they are closely in contact with each other at one end of the organization and separate from each other progressively towards the other end of said organization.

When a load is applied to the composite spring a deflection by compression of the outer spring I2 takes place equally all over its length, but the compression of the inner spring II is in proportion to its diameter at any given point along its length, that is, the deflection at thevbottom, see Figs. 2 and 3, is the greatest and it decreases in proportion to the distance Iromthe bOttUm. NOW,

the inner and outer sprlngs'will come in contact with each other, step by step, from the bottom to the upper end due to the imposed load, and at the zone where they are in contact with each other, they are compressedv downwardly, and also .y

the formerconical section is compressed inwardly and the outer cylindrical section is expandedoutf wardly, due 'tothe horizontal components of a f ,y force acted upon their inclined surfaces. Alateral deformation of the inner spring will be very 10 little, as its shape is conical. i

At the zone where the inner andthe outer v Y springs are in contact with each other, thelatter will be stressed or expanded outwardly, and lits resistance will react to cause compression of the 15 former downwardly and inwardly. The frictional resistance'induced between ythe spring sections Y will decrease according .to the distance from the small diameter end of the conical spring and thev resistance will increase according to load accu- 20 v muiation. Tendency to a permanent setting of f the organization is reduced by my organization.

In general, the larger the cross sectional area of the material, the more diflicult heat treatments of springs will be, and the manufacturing of ,25'

springs which are to be subjected to great loads,

' as for vehicles, is technically very difficult. However, according to my invention, the manufacturing of the organization is easy, because the material is very small in diameter as compared with 36".

previously known springs.

Where conical spiral springs rII and I3 are screwed into place in the organization from oppo' site ends of a cylindricalspiral spring I2 of Fig.

2, asy shown in Fig. 5, the characteristic is better4 `3`5 y thanl the above example upon comparison as eas; ily seen from Fig. 8, in which curves A and B indicate relations between load and deflection of the above and the present examples respectively.

If the conical spiral spring II is made by a 40 Having described my invention as above, what I claim is:

' 1. A spiral spring Vorganization comprising an outer spiral section of generally cylindrical form and an inner spiral section of generally'conic'zsilV iorm screwed into the outer section, the said 5.5:

sections at one end being initially in contact and diverging from each other towards the other end with progressively enlarged spacinbetween the opposed surfaces of said sections, substantially as described.

2. A spiral spring organization comprising an outer spiral section of generally cylindrical form and an innerfspiral section of generally conical a,ose,s21 4 form screwed into the outer section, the said sec-v l tions having inclined faces at their opposing sides only, said faces being in contact at one end of the organization and spaced apart at greater distances progressively towards the other end of the organization.

HIOJIRD KUDO. 

